Refrigerator cabinet having means to improve temperature distribution



Dec. 1952 J. A. PIETSCH REFRIGERATOR CABINET HAVING MEANS TO IMPROVE TEMPERATURE DISTRIBUTION Filed Nov. 23, 1951 Pi gl.

Inventor:

SJ m h) E t w .e n p r A. m h M DI e .s S H O Patented Dec. 16, 1952 REFRIGERATOR CABINET HAVIN G MEAN S TO IMPROVE TEMPERATURE DISTRIBU- TION Joseph A. Pietscl, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York Application November 23, 1951, Serial No'.,257,764

3 Claims.

This invention relates to refrigerator cabinets, more'particularly to such cabinets having a front opening normally closed by a door, and it h-as for its object the provision of an improved cabinet of this character which, by its wall arrangement, improves the temperature distribution of the air within the cabinet.

While this invention is applicable to refrigerator cabinets in general, it is especially useful in the low temperature, relatively small reezer cabinets employed in household refrigerators such as those formed or constructed with a relatively large higher temperature food storage compartment, as in the so-called Two-Temperature" refrigerator.

In one type of these small freezer compartments, the evaporator cooling coils are placed along the top, bottom and end walls to 'extract heat from the compartment and thereby cool it. I have found that in these compartments the temperature distribution of the air is such that the warmest zone is at the top forward part of the compartment directly inside the front door opening. This is due to the fact that each time the door is opened some of the warm air from the outside the refrigerator enters and collects in a pocket at the upper forward end of the compartment. Also, -air enters the compartment and collects at the forward end due to leakage at the door even when the door is closed; furthermore, heat leakage at the door while it is closed has much the same effect as a door opening.

This invention contemplates an improved cabinet Construction arranged to improve substantially the temperature distribution in the cabinet, that is, which reduces materally the temperature differential between the warmest and coolest air zones in the compartment. And this invention efiects this improvement by sloping the upper wall of the freezing compartment upwardly from theiront door to the rear of the compartment. This upwardly sloping top wall enables the air which would tend to collect in a warm pocket at the front to rise by convection toward the back of the compartment along the top wall which cools the air as it ows. The cooled air then drops toward the bottom, and so the circulation of air in the compartment is increased. I have found that this arrangement lessens the temperature difierential in the compartment to a material extent, that is, effects a more even temperature distribution throughout the compartment.

For a more complete understanding of this invention, reference should be had to the accompanying drawing in which Fig. 1 is a vertical sec- 2, tional view of -a portion of a two-temperature refrigerator embodying this invention; and .Fig. 2 is a viewsimilar to'Fig. 1 but illustrating a conventional refrigerator cabinet.

Referring to the drawing, this invention'has been shown in one form as applied'to a two-temperature refrigerator comprising an upper freezing cabinet l maintained at a relatively low temperature as, for example, from zero degrees to 10 F., and a lower food storage compartment 2 maintained'at some suitable food storing temperature, such as 38 F. The upper compartment is formed by an inner metallic lining having a top wall 3, a horizontal bottom wall 4, a vertical rear w-all 5, and a pair of vertical, substantially parallel side walls 5a (only one of which is shown), all of these walls being joined together in any suitable way so as to form a box-like storage space having an opening 6 at the front. The food storage compartment 2 likewise has an inner metallic lining formed from a horizontal top wall 1, a vertical rear wall 8, vertical and parallel side walls sa (only one of which is shown), and a bottom wall (not shown) opposite the top wall, these walls also being joined together to form a box-like cabinet having a front opening 9. V ,w

The two compartments l and 2 are separated from each other by an insulating layer o, which insulates the bottom wall 4 of compartment I and the top wall 1 of compartment 2. A layer ll of insulation insulates the rear walls 5 and 8 of the twocompartmenta a'nd a layer l2 of insulation insulates the top wall 3 of the upper compartment. It will be understood, of course, that the bottom wall of compartment 2 also will be provided with an insulating layer. The whole of the foregoing Construction is enclosed by an outer metallic cabinet having a top wall l 3, a rear wall I 4, a front wall !5, and parallel side and bottom walls (not shown) to form a substantially box-like outer shell or cabinet having openings aligned with the openings 6 and 9 of the two compartments.

The metallic walls of the freezer compartment l at the front are separated from the front wall l5 of the outer shell by means of 'a breaker strip !6, while the metallic walls of compartment 2 are separated from the front wall IS by means of a breaker strip ll, the two breaker strips IS and ll being formed of any suitable heat insulating material.

As shown in the case of each compartment l, 2, the forward end portions of the top, bottom and side walls are tapered inwardly toward their respective front openings so that the throats of the openings are somewhat smaller than the vertical cross sections of the respective Compartments; this Construction, however, is not necessary, since the openings may be just as large as the vertical cross sections of the respective compartments. These openings are provided with heat insulating doors !8 and 19 respectively.

The top, bottom and end Walls 3, 4 and 5 of the freezer compartment l are cooled by evaporator coils 20 fixed to these walls at substantially uniformly spaced intervals from the front to the rear of the top and bottom Walls and from the top to bottom of the rear wall, as shown.

In accordance with this invention, I have arranged the top wall 3 so as to reduce materially the temperature diiferential between the upper front corner and lower rear corner, and I do this by sloping the upper Wall 3 from the front to the rear, as shown; in the specific example of the invention illustrated, I give the wall a 5 slope.

By reason 'of this arrangement the warm air which tends to collect in the upper forward part in a pocket rises by conve'ction toward the rear of the compartment t along the top sloping wall 3 and as it s'o moves, it is coole'd by the evaporator coils '20 suificiently to cause it to drop toward the bottom of the co'r'npartment by convection action, as shown by the arrows in Fig. 1. The sloping top wall facilitates and increases the circulation of air' in the com'partment and materially reduces the temperature differential. I have found by actal test that by giving the top wall a slope of 5 the temperature difierential between the upper forward part of the -cabint and the lower rear corner therof is rdice'd by approximately 25 The lines 2! of Fig l are isothermal lines and they indicate a 1 dierntial in temperature from one to the other, that is, a 1 rise in temperature from the lower to the 'next higher line. It will be observed in Fig. 1 th'at there is but a 6 rise in temperature from the lower coolest area of the compartment at the 'rear lower corner to the upper warmest area of the compartment at the front upper corner,

By contrast in Fig. 2 (drawn to a smaller scale than is Fig. 1) there is illustrated a conventional freezer compartment 22 of the same dimensions as the cabinetofFig 1 and having substantially horizontal bottom and top walls 23 and 24, a vertical rear wall 25, and apair of side vertical Walls 25 (on1y one shown). These walls are joined together to define the compartment 22 and to provide a front opening 21 for it. These walls are provideclwith an insulating layer 28 which is housd within an outer cabinet 29. The front opening is closed by a door 30, and the bottom, top, and end walls 23, 24, and 25 arecooled by evaporator coils 3! uniformly spaced along these walls, as shown. In this conventionalcompart ment which has substantially the same Volume as has the compartment i of Fig. 1, the temperature differential from the lower left-hand corner,

which is the coolest, to the upper right corner, which is the warmest, is denoted by the isothermal lines indicating 1 temperature rise from one to the other from the lower to the upper part of the cabinet, that is, a temperature rise of 8 as contrasted with the 6 rise in Fig. 1. In other words, the 5 sloping top of Fig. 1 reduces the temperature differential by about 25%. This improvement can be accentuated by giving the top wall a greate' slope than 5.

While I have shown a particular embodiment of my invention, it will be understood, of course, that I do not wish to be limited thereto since many m'odifications may be made, and I therefore contem'plate by the appended claims to cover any such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A refrigerator cabinet comprising a substantially horizontal bottom wall, substantially vertical side and rear walls, and a top wall all joinecl together to form a refrigerator compartment having an opening at the front, a door for said opening, said top wall sloping upwardly from said. opening to said rear wall, and cooling means fo i' cooling at least said top wall from the front to the rear thereof.

2. A refrigeratcr cabinet comprising a substantially horizontal bottom wall, substantially vertical side and rear walls, and a top wall all joined together to form a refrigerator compartment having an opening at the front, a door for said opening, said top' wall having a substantially uniform slope from the front opening to said rear wall and cooling means for cooling said top and bottom walls from the front to the rear there of and saidrear wall from the top to the bottom portion thereof.

g 3. A refrigerator cabinet comprising a substantially horizontal bottom wall, substantially vertical side and rear walls, and a top wall all joined together to form a refrigerator compartment having an opening at the front, a door for said opening, said top wall sloping upwardly from the said opening to said rear wall and evaporator cooling coils in contact with said top, bottom and rear walls spaced at substantially uniform inter- Vals along the walls. v

J OSEPI-I A. PIETSCH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 11313468 McClafferty Jan. 4, 1927 2,363,530 Iwashita Nov. 28, 1944 2,499,089 Brill Feb. 28, 1950 2,5o9,611 Philipp May 30, 1950 

